1. Field
Embodiments of the present invention relate to a variable pedal feeling adjustment device, and more particularly to, a variable pedal feeling adjustment device capable of adjusting pedal feeling by increasing and decreasing a moving distance of a reaction piston of a pedal simulator.
2. Description of the Related Art
In general, an active hydraulic boost (AHB) is a brake system that generates braking force when a driver pushes a pedal by sensing the push through an electronic control unit and supplying hydraulic pressure to a master cylinder through operation of a hydraulic pressure generation unit, thereby transferring hydraulic brake pressure to a wheel cylinder of each wheel. In the case of such an AHB, when a driver pushes the brake pedal during normal braking, a pedal displacement sensor senses displacement of the brake pedal. The electronic control unit operates the hydraulic pressure generation unit and controls supply of hydraulic oil stored in a hydraulic oil reservoir to a boost chamber of the master cylinder to produce pressure in the master cylinder. The pressure produced in the master cylinder presses a piston in the master cylinder to produce hydraulic brake pressure. This hydraulic brake pressure is transferred to the wheel cylinder to produce braking force.
In the case in which pressure in the master cylinder changes during regenerative braking, the resulting force may be directly transferred to the brake pedal, thereby adversely affecting pedal feeling. If the pedal feeling is degraded in this way, a large difference occurs between pedal feeling that a driver receives in braking and an actual level of pressure applied to a brake disc of a brake pad in the wheel cylinder, resulting in excessive or insufficient braking. Thereby, disposable components such as a brake pad may need to be frequently replaced and sudden braking or failure of braking leading to a traffic accident may occur.
In conventional cases, a pedal simulator is adopted for the AHB to provide reaction force to the brake pedal. Such a pedal simulator uses, as disclosed in Korean Patent No. 10-0657576, two springs provided therein as shock absorbing members to absorb shock to a simulator piston. However, the two springs merely produce brake pedal feeling linearly varying along the straight lines as shown in FIG. 1, and may not provide required pedal feeling.
Further, because the springs have the limited performance in providing reaction force, the conventional pedal simulator may not adjust pedal feeling that a driver receives.